代码示例：（标识：bs_grid_ex_structure）
<!DOCTYPE html>
<html lang="en">
<head>
<title>Bootstrap Example</title>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<link href="https://cdn.bootcdn.net/ajax/libs/twitter-bootstrap/5.1.2/css/bootstrap.min.css" rel="stylesheet">
<script src="https://cdn.bootcdn.net/ajax/libs/twitter-bootstrap/5.1.2/js/bootstrap.bundle.js"></script>
</head>
<body>
<div class="container-fluid mt-3">
<h1>基本网格结构</h1>
<p>请调整浏览器窗口大小来查看效果。</p>
<p>当屏幕宽度小于 576px 时，第一行、第二行和第三行会自动堆叠在一起。</p>
<!-- 控制列宽，以及它们在不同设备上的显示方式 -->
<div class="row">
<div class="col-sm-6 bg-primary text-white">50%</div>
<div class="col-sm-6 bg-dark text-white">50%</div>
</div>
<br>
<div class="row">
<div class="col-sm-4 bg-primary text-white">33.33%</div>
<div class="col-sm-4 bg-dark text-white">33.33%</div>
<div class="col-sm-4 bg-primary text-white">33.33%</div>
</div>
<br>
<!-- 或者让 Bootstrap 自动处理布局 -->
<div class="row">
<div class="col-sm bg-primary text-white">25%</div>
<div class="col-sm bg-dark text-white">25%</div>
<div class="col-sm bg-primary text-white">25%</div>
<div class="col-sm bg-dark text-white">25%</div>
</div>
<br>
<div class="row">
<div class="col bg-primary text-white">25%</div>
<div class="col bg-dark text-white">25%</div>
<div class="col bg-primary text-white">25%</div>
<div class="col bg-dark text-white">25%</div>
</div>
</div>
</body>
</html>
